| WHITESPACE = _{ " " | "\t" } | |
| // TODO: Proper indentation and formatting | |
| program = _{ SOI ~ expr ~ EOI } | |
| expr = { atom ~ (infix ~ atom)* } | |
| atom = _{ prefix? ~ primary ~ postfix? } | |
| infix = _{ add | sub | mul | div | pow | paren } | |
| add = { "+" } // Addition | |
| sub = { "-" } // Subtraction | |
| mul = { "*" } // Multiplication | |
| div = { "/" } // Division | |
| mod = { "%" } // Modulo | |
| pow = { "^" } // Exponentiation | |
| paren = { "" } // Implicit multiplication operator | |
| prefix = _{ neg | sqrt } | |
| neg = { "-" } // Negation | |
| sqrt = { "sqrt" } | |
| postfix = _{ fac } | |
| fac = { "!" } // Factorial | |
| primary = _{ ("(" ~ expr ~ ")") | lit | constant | fn_call | ident } | |
| fn_call = { ident ~ "(" ~ expr ~ ("," ~ expr)* ~ ")" } | |
| ident = @{ (ASCII_ALPHA | "_") ~ (ASCII_ALPHANUMERIC | "_")* } | |
| lit = { unit | ((float | int) ~ unit?) } | |
| float = @{ int ~ "." ~ int? ~ exp? | int ~ exp } | |
| exp = _{ ^"e" ~ ("+" | "-")? ~ int } | |
| int = @{ ASCII_DIGIT+ } | |
| unit = ${ (scale ~ base_unit) | base_unit ~ !ident} | |
| base_unit = _{ meter | second | gram } | |
| meter = { "m" } | |
| second = { "s" } | |
| gram = { "g" } | |
| scale = _{ nano | micro | milli | centi | deci | deca | hecto | kilo | mega | giga | tera } | |
| nano = { "n" } | |
| micro = { "µ" | "u" } | |
| milli = { "m" } | |
| centi = { "c" } | |
| deci = { "d" } | |
| deca = { "da" } | |
| hecto = { "h" } | |
| kilo = { "k" } | |
| mega = { "M" } | |
| giga = { "G" } | |
| tera = { "T" } | |
| // Constants | |
| constant = { infinity | imaginary_unit | pi | tau | euler_number | golden_ratio | gravity_acceleration } | |
| infinity = { "inf" | "INF" | "infinity" | "INFINITY" | "∞" } | |
| imaginary_unit = { "i" | "I" } | |
| pi = { "pi" | "PI" | "π" } | |
| tau = { "tau" | "TAU" | "τ" } | |
| euler_number = { "e" } | |
| golden_ratio = { "phi" | "PHI" | "φ" } | |
| gravity_acceleration = { "G" } | |